Vibrator



C. F. COAKE July 12, 1949.

VIBRATOR Filed April 18, 1946 INVENTOR CHARLES H COAKE BY ORNEY Patented July 12, 1949 v z,41.5,a zo

UNITED STATES PATENT OFFICE vnma'ron. I

ration of Indiana Application April 1a, 1945, S mi No. 663,200

This invention relates to electromagnetic vibrators and has for its'obiect to simplify the construction and increase the operfit s emciency of such devices.

Another object of the invention the maximum contact area betweentbe contacts of an electromagnetic vibrator under gall operating conditions. Y

Another object is to provide a I a novel combination of inner and-outer flexible contact arms in which the ratiooficompliances of said arms is such as to maintain con tacting surfaces parallel under all ditions of use.

Still another object is to provide an electromagnetic vibrator of the foregoingv type having novel and improved details of construction and features of operation.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

The invention will be described in its application to a miniature vibrator of the type disclosed in my copending application Serial No. 663,199, filed April 18, 1946, and copending application Serial No. 532,962. filed April 27, 1944 in which a vibratory reed carrying a pair of inner contact arms is enclosed in a compact skeleton frame of cylindrical contour containing a driver coil and a pair of outer contact arms cooperating with the contact arms carried by the reed.

The invention resides in a simplified combination of inner and outer contact arms in a vibrator of the abovetype, in which the compliances (i. e., the reciprocal of stiffness) of said arms are such as to maintain their power contacts parallel throughout the operating range. By thus maintaining the cooperating contacts para lel and preventing them fromrocking on each other, I maintain the maximum contact area under all operating conditions and thereby improve the contact eillciency and prolong the life of the contacts.

Although the novel features which are characteristic of this invention are set forth more in detail in the claims appended hereto, the nature and scope of the invention may be better understood by referring to the following description,

taken in connection with the accompanying draw- I ing forming a part thereof, in which a specific embodiment has been set forth for purposes of illustration.

In the drawing:

Fig. 1 is a longitudinal sectional view of an coil ll having a pole piece I2, a vibratory reed 0 Claims. (Cl. zoo-sci electromagnetic vibrator embodying the present invention; and

Fig. 2 is an exploded perspective view of the frame, vibratory reed and contact assembly of the vibrator.

In the following description certain specific terms are used for convenience in referring to the various details of the invention. These terms, however, are to be interpreted as broadly as the state of the art will permit.

In the drawing, I have shown an electromagnetic vibrator comprising a pair of elongated magnetic frame members in supporting a driver It secured to clamping base plates ll which are seated in an insulating disc i5, inner -contact arms 18 which are secured to opposite sides of the reed l3, and outer contact arms I! which are secured to and insulated from the frame members l0 and cooperate with the respective inner arms It as hereinafter more fully described.

The magnetic frame members In are preferably stamped out of sheet metal and are curved transversely throughout their length. Each frame member has a pair of outwardly extending arms it which are secured as by welding to the corresponding arms of the other frame member when the two members are brought together as shown in Fig. 1. The ends of the frame members adjacent the arms 18 comprise arcuate collars I! which partly surround a disc Ila carrying the driver coil H and are secured thereto as by welding. The opposite ends of the frame members It are welded to the clamping plates H, as shown in Fig. 1.

The vibratory reed I3 is formed with an upward taper in width and has an armature 22 of magnetic material secured to its upper or free end as by welding. When the vibrator is assembled, as shown in Fig. 1, the armature 22 is encompassed by the arms 18 of the magnetic frame members l0 and is spaced only slightly from said arms and from the pole piece l2, thus forming a magnetic flux path of low reluctance which increases the sensitivity of the instrument. The lower extremity of the reed ends in two extensions or cars 23connected with the body of the reed by means of weakened portions 2| constituting hinges which facilitate setting the reed in vibration upon energization ofv the driver coil II. The cars 23 of the reed are secured to tabs 28 of the plates ll as by welding. The depending lugs 26 and the ears 23 are seated'in radial slots 21 in the insulating disc II when the plates ii are seated on the disc'asshown'inllig. 1.

The two inner contact arms II, which are secured to Opposite sides of the vibratory reed ii, are preferably stamped out of flexible sheet metal and each comprises a pair of spaced parallel resilient side arms 3| having their ends connected by top and bottom yokes or cross arms 32 and 33, respectively, and an inner arm or tongue 34 projecting from the center of the top yoke 32 into the space between the side arms 3| and carrying a contact 35 having a flat contact surface. The bottom yokes 33 are bent transversely along a line 38 and the portions of said yokes below the bend it are secured to the reed l3 by riveting or welding, so that the entire contact arm it above the bend at stands out from the reed II at an angle and the two contact arms it together form a V-shape as shown in Fig. 1. Since the bend line 36 is in the rigid part of the contact arm below the point where the flexible side arms 3| start, the effective length and tuning of the side arms 3| will remain unchanged even though the precise location of the bend 36 may vary slightly in different stamping operations.

The two outer contact arms H, in the embodiment illustrated herein, are similar to the inner contact arms l6, and they have therefore been given similar reference numerals, but with primes aflixed thereto. However, the outer contact arms II are inverted with respect to the inner arms i6 and have their yokes 33 secured by bolts 38 and insulating spacers .39 to the respective frame members iii. The free portions of the outer contact arms II project downwardly at an angle to bring the contacts adjacent and parallelto the contacts 35 of the respective inner contact arms IS.

The compliance of the various contact arms i6 and I1 is the sum of the compliances of the component parts of said arms. Considering either of the inner contact arms It, for example, one of such component parts extends from the base of the free side arms 3| to the line of the contact 35, as designated a in Fig. 2. The other component part of said arm I6 is the U-shaped distance b from the aforesaid line of the contact 35 up the arm 3i, across/the yoke 32 and down the arm 34 to the contact 35. Likewise with regard to the cooperating outer contact arm i1,

one of the component parts extends from the base of the free side arms II" to the line of the contact 35 as indicated by c in Fig. 2. The other component part of said arm 11 is the U-shaped distance d from the line of the contact 35' down the arm 3|, across the yoke 32 and up the arm 34' to the contact 35'. r

I have discovered that in the case of a vibrator, such as illustrated herein, where both of the cooperating contact arms contain a reverse bend, a ratio of compliances of a=c, and b=d, will result in maintaining the cooperating contacts 35 and 35 parallel to each other when flexed. Furthermore, in a specific and sometimes preferred case where a=b==c=d, the cooperating contacts 35 and 35' will not only remain parallel to each other when flexed, but will also remain in planes parallel to their original plane throughout the operating range. In either case the contacts will always engage in flat face-to-face contact and maintain the maximum contact area under all operating conditions, thereby improving the contact efliciency and prolonging the life of the contacts.

Although a specific embodiment has been shown and described herein for purposes of illustration,

4 it will be evident to those skilled in the art the the invention is capable of various modification and adaptations within the scope of the appendei claims.

What is claimed is:

1. An electromagnetic vibrator comprising vibratory reed, a pair of inner contact arm carrying contacts mounted on opposite sides 0 said reed, and a pair of rigidly supported oute contact arms carrying contacts for engagemen with the contacts of the respective inner contac arms, each of said contact arms having a pal of resilient side arms, a yoke connecting the fre' ends of said side arms, and a tongue projectinl from said yoke into the space between said sid arms and carrying the aforementioned contact the cooperating inner and outer contact arm. being mounted to extend in opposite direction from their fixed ends and having a ratio of com pliances selected to maintain their cooperatin contacts parallel.

2. An electromagnetic vibrator comprising vibratoryreed, a pair of inner contact arm. carrying contacts mounted on opposite sides 0 said reed, and a pair of rigidly supported cute: contact arms carrying contacts for engagemen with the contacts of the respective inner contac arms, each of .said contact arms having a pair 0: resilient side arms, a yoke connecting the ire ends of said side arms, and. a tongue projecting from said yoke into the space between said Sidi arms and carrying the aforementioned contact the cooperating inner and outer contact arm; being mounted to extend in opposite direction; from their fixed ends and having a ratio of compliances selected according to the formulae (1:1 and b=d. where a and 0 represent the com pliances of the side arms of the cooperating contact arms from their supports to their contac lines, and b and d represent the compliances o; the cooperating contact arms from said contact lines around the yokes to the contacts themselves 3. An electromagnetic vibrator comprising a vibratory reed,'a pair of inner contact arm: carrying contacts mounted on opposite sides 01 said reed, and a pair of rigidly supported outei contact arms carrying contacts for engagemeni with the contacts of the respective inner contact arms, each of said contact arms having a pair oi resilient side arms, a .yoke connecting the free ends of said side arms, and a tongue projecting from said yoke into the space between said side arms and carrying the aforementioned contact the cooperating inner and outer contact arms being mounted to extend in opposite directions from their fixed ends and having a ratio of compliances selected according to the formula where a and c represent the complianccs of the side arms of the cooperating contact arms from their supports to their contact lines. and b and d represent the compliances of the cooperating contact arms from said contact lines around the yokes to the contacts themselves.

4. An electromagnetic vibrator comprising a base plate, a vibratory reed secured to said plate, an armature on the free end of said reed, a U-shaped frame secured to said plate on both sides of said reed, a driver coil secured to said frame and having a. pole piece adjacent said armature, a pair of inner contact arms mounted on opposite sides of said reed each having an end yoke secured to said reed, a pair of side arms connected to said yoke, a second end yoke connecting the outer ends of said side arms and a tongue having a fiat contact projecting downwardly between said side arms from the center of said second yoke, and a pair of outer contact arms each having an end yoke secured to and insulated from said frame, a pair of side arms connected to said yoke and extending toward said base plate parallel to the inner contact arms, another end yoke connecting the outer ends of said side arms and a tongue projecting upwardly between said side arms from the center of said other end yoke and having a, flat contact for engagement with the contacts of the respective inner contact arms.

5. An electromagnetic vibrator comprising a base plate, a vibratory reed secured to said plate, an armature on the free end of said reed, a U-shaped frame secured to said plate on both sides of said reed, a driver coil secured to said frame and having a pole piece adjacent said armature, a pair of inner contact arms mounted on opposite sides of said reed each having an end yoke secured to said reed, a pair of side arms connected to said yoke, a second end yoke connecting the outer ends of said side arms and a tongue having a flat contact projecting downwardly between said side arms from the center of said second yoke, and a pair of outer contact arms each having an end yoke secured to and insulated from said frame, a pair of side arms connected to said yoke and extending toward said base plate parallel to the inner contact arms, another end yoke connecting the outer ends of said side arms and a tongue projecting upwardly between said side arms from the center of said other end yoke and having a flat contact for engagement with the contacts of the respective inner contact arms, the cooperating inner and outer contact arms having a ratio of compliances selected to maintain their cooperating contacts parallel.

6. An electromagnetic vibrator comprising a base plate, a vibratory reed secured to said plate,

an armature on the free end of said reed, a U-shaped frame secured to said plate on both sides of said reed, a driver coil secured to said frame and having a pole piece adjacent said armature, a pair of upwardly extending inner contact arms mounted on opposite sides of said reed each having an end yoke secured to said reed, a pair of side arms connected to said yoke, a second end yoke connecting the outer ends of said side arms and a tongue having a fiat contact projecting downwardly between said side arms from the center of said second yoke, and a pair of downwardly extending outer contact arms each having an end yoke secured to and insulated from said frame, a pair of side arms connected to said yoke, another end yoke connecting the outer ends of said side arms and a tongue projecting upwardly between said side arms from the center of said other end yoke and having a flat contact for engagement with the contacts of the respective inner contact arms, the compliances of the cooperating inner and outer contact arms being selected according to the formulae a=c and b=d, where a and c are the compliances of the side arms of said contact arms from their supporting yokes to their contact lines, and b and d are the compliances of said contact armsfrom said contact lines around the yokes to the contacts themselves.

- CHARLES F. COAKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,068,093 Teriesen Jan. 19, 1937 2,197,607 Brown Apr. 16, 1940 2,200,064 James May '7, 1940 2,213,854 Wood Sept. 3, 1940 2,272,855 Sullivan Feb. 10, 1942 2,334,769 Huetten Nov. 23, 1943 

